I have a dataframe of actor names:
df1
actor_id actor_name
1 Brad Pitt
2 Nicole Kidman
3 Matthew Goode
4 Uma Thurman
5 Ethan Hawke
And another dataframe of movies that the actors were in:
df2
actor_id actor_movie movie_revenue_m
1 Once Upon a Time in Hollywood 150
2 The Others 50
2 Moulin Rouge 200
3 Stoker 75
4 Kill Bill 125
5 Gattaca 85
I want to merge the two dataframes together to show the actors with their movie names and movie revenues, so I use the merge function:
df3 = df1.merge(df2, on = 'actor_id', how = 'left')
df3
actor_id actor_name actor_movie movie_revenue
1 Brad Pitt Once Upon a Time in Hollywood 150
2 Nicole Kidman Moulin Rouge 50
2 Nicole Kidman The Others 200
3 Matthew Goode Stoker 75
4 Uma Thurman Kill Bill 125
5 Ethan Hawke Gattaca 85
But this pulls in all movies, so Nicole Kidman gets duplicated, and I only want to show one movie per actor. How can I merge the dataframes without "duplicating" my list of actors?
How would I merge the movie title that is alphabetically first?
How would I merge the movie title with the highest revenue?
Thank you!
One way is to continue with the merge and then filter the result set
movie title that is alphabetically first
# sort by name, movie and then pick the first while grouping by actor
df.sort_values(['actor_name','actor_movie'] ).groupby('actor_id', as_index=False).first()
actor_id actor_name actor_movie movie_revenue
0 1 Brad Pitt Once Upon a Time in Hollywood 150
1 2 Nicole Kidman Moulin Rouge 50
2 3 Matthew Goode Stoker 75
3 4 Uma Thurman Kill Bill 125
4 5 Ethan Hawke Gattaca 85
movie title with the highest revenue
# sort by name, and review (descending), groupby actor and pick first
df.sort_values(['actor_name','movie_revenue'], ascending=[1,0] ).groupby('actor_id', as_index=False).first()
actor_id actor_name actor_movie movie_revenue
0 1 Brad Pitt Once Upon a Time in Hollywood 150
1 2 Nicole Kidman The Others 200
2 3 Matthew Goode Stoker 75
3 4 Uma Thurman Kill Bill 125
4 5 Ethan Hawke Gattaca 85